By Zsuzsanna Végh in Berlin Péter Magyar has appeared from nowhere this spring to become Hungarian Prime Minister Viktor Orbán’s main challenger. But he may pose a greater threat to the fragmented democratic opposition than to Orban himself. Former justice minister Judit Varga’s ex-husband was a regime insider and virtually unknown to the wider public until his public about-face in February. He entered the political scene following the scandal over President Katalin Novák’s pardon in a sexual abuse case that had taken place in a state-run children’s home. The scandal led to the resignation of …